Memory device

1. A memory device, comprising:

an array of memory cells configured to provide resistive states;

a read circuit configured to sense the resistive states; and

a resistor configured to provide a resistance to the read circuit that is configured to select the resistor and sense the resistance to test the read circuit.

2. The memory device of claim 1 , wherein the read circuit is configured to receive a digital test pattern and provide an output signal indicating a change in the digital test pattern.

3. The memory device of claim 1 , wherein the read circuit is configured to receive a ramped waveform and provide an output signal indicating dynamic response of the read circuit.

4. The memory device of claim 1 , wherein the read circuit is configured to receive a calibration signal and provide an output signal indicating calibration changes in the read circuit.

5. The memory device of claim 1 , wherein the read circuit is configured to receive a reference signal and provide an output signal indicating the resistive states of the memory cells.

6. The memory device of claim 1 , wherein the read circuit is configured to select the resistor and sense the resistance to test functionality of the read circuit.

7. The memory device of claim 1 , wherein the read circuit is configured to select the resistor and sense the resistance to calibrate the read circuit.

8. The memory device of claim 1 , wherein the read circuit is configured to select the resistor and sense the resistance to determine a reference signal value for distinguishing the resistive states of the memory cells.

9. The memory device of claim 1 , wherein the resistor is an N well diffusion resistor.

10. The memory device of claim 1 , wherein the resistor is a polysilicon resistor.

11. The memory device of claim 1 , wherein the resistor is tuned to provide a resistance value.

12. The memory device of claim 1 , wherein the resistor is a resistor array configured with fuses for tuning the resistance value.

13. The memory device of claim 1 , wherein the resistor is laser trimmed to tune the resistance value.

14. The memory device of claim 1 , wherein the array of memory cells is an MRAM array of magnetic memory cells.

15. The memory device of claim 1 , wherein the array of memory cells is an anti-fuse array of memory cells.

16. The memory device of claim 1 , wherein the array of memory cells is part of an integrated circuit chip and the resistor is part of the integrated circuit chip.

17. The memory device of claim 1 , wherein the array of memory cells is part of an integrated circuit chip and the resistor is located outside the integrated circuit chip.

18. The memory device of claim 17 , wherein the resistor is a metal thin film resistor.

19. The memory device of claim 17 , wherein the resistor is a 1% precision resistor.

20. A memory device, comprising:

a memory cell configured to provide a first resistive state and a second resistive state;

means for sensing the first resistive state and the second resistive state;

means for providing a first resistance to the means for sensing; and

means for providing a second resistance to the means for sensing, wherein the means for providing a first resistance corresponds to the first resistive state and the means for providing a second resistance corresponds to the second resistive state.

21. The memory device of claim 20 , wherein the means for sensing is configured to receive a functional test pattern and provide an output signal corresponding to the functional test pattern.

22. The memory device of claim 21 , wherein the functional test pattern is a digital test pattern.

23. The memory device of claim 20 , wherein the means for sensing is configured to receive a dynamic response test waveform and provide an output signal indicating dynamic responses of the means for sensing.

24. The memory device of claim 23 , wherein the dynamic response test waveform is a ramped waveform.

25. The memory device of claim 20 , wherein the means for sensing is configured to receive a calibration signal and provide an output signal to indicate calibration changes in the means for sensing.

26. The memory device of claim 20 , wherein the means for providing a first resistance and the second means for providing a second resistance are used to obtain a reference signal for distinguishing the first resistive state and the second resistive state of the memory cell.

27. The memory device of claim 20 , wherein the means for providing a first resistance and the means for providing a second resistance are tuned to provide resistance values to the means for sensing.

28. A method of testing a magnetic memory device comprising an array of magnetic memory cells, the method comprising:

providing a read circuit in the magnetic memory device;

providing a resistor that differs structurally from magnetic memory cells in the array of magnetic memory cells;

sensing the resistance through the resistor with the read circuit to obtain a result; and

comparing the result to expected results.

29. The method of claim 28 , wherein providing the resistor comprises providing an N-well that is highly doped to provide a linear resistance characteristic.

30. The method of claim 28 , wherein providing the resistor comprises providing a winding resistor body to conserve space and achieve a resistance value.

31. The method of claim 28 , wherein sensing the resistance comprises applying a functional test pattern to the read circuit that provides a corresponding output signal.

32. The method of claim 28 , wherein sensing the resistance comprises applying a dynamic response test waveform to the read circuit that responds with the dynamic response of the read circuit.

33. The method of claim 28 , further comprising,

sensing the resistance through the resistor to obtain a reference signal for distinguishing resistive states of the magnetic memory cells;

applying the reference signal to the read circuit; and

obtaining resistive states of the magnetic memory cells.